This invention relates to a knitted fabric panel structure and to a process of manufacture of the structure.
U.S. Pat. No. 3,481,427 discloses a three-dimensional woven fiberglass fabric impregnated with resin to create a rigid structural panel having intermediate spaced apart walls of ribbed cores forming dead air cavities. Because the woven structure tends to readily sag after resin hardening backup structure must be inserted in the cavities. This, however, results in a quite expensive production.
Resin-hardened fiber compounds have gained widespread use as structural panels or as sound absorbing elements. Such panels are used in aircraft structure because of their light weight, maximum rigidity and resistance to compression characteristics.
Weaves such as weft velvet and warp velvet may be used in weaving the three-dimensional panel. For economical production a double layer panel is made in the form of a so-called double velvet in which the pile threads used as connecting ribs between the layer-forming velour threads form a double layer. The length of the floating threads is adjustable so that various rib lengths can be effected. The pile threads are then cut between their ends on a cutting bench.